Arq. NeuroPsiquiatr. vol.75 número10

(1)

762

https://doi.org/10.1590/0004-282X20170115

OPINION

Congenital Zika virus infection in

twin pregnancies

Infecção pelo Zika virus em gravidez gemelar

Dear Editor,

he publication on “Congenital Zika virus infection in twin pregnancies” is very interesting1_{. Linden et al. reported} on “two cases of twin pregnancies exposed to the Zika virus, but with only one of the fetuses afected with microcephaly and brain damage1_{.” Indeed, the transplacental transmission} of the Zika virus has been conirmed and direct cytopathol

-ogy due to the virus is possible2_{. Nevertheless, not all cases} of infection will result in symptomatic clinical manifesta

-tion and most cases are usually asymptomatic3_{. In the case of} identical twins exposed to the virus, if there is discordance of susceptibility, it might imply that there may be little or no role of the genetic background on susceptibility or resistance to the virus. Nevertheless, there can also be some other explana

-tions for the discordance. Firstly, there might be some variant

in the placenta and umbilical cord, or in the infant, and this might act as a preventive barrier to infection. In the report by Linden et al.1_{, there is no data on the placenta and umbilical} cord, hence we cannot draw a inal conclusion on this issue. Secondly, the disorder in the abnormal fetus might be due to another cause, such as a somatic mutation, which might occur sporadically. Since there is no complete genetic workup comparing the normal and abnormal twin fetuses, and there is also no proof of viral infection in both fetuses, the conclusion also cannot be reached. Finally, although the mother might get the infection, and as transplacental transmission is possi

-ble, virus identiication in both fetal brain and umbilical cord is required for conirmation of actual vertical transmission4_.

Beuy Joob1_{, Viroj Wiwanitkit}2

1_{Sanitation 1 Medical Academic Center, Bangkok Thailand;} 2_{Hainan Medical University, China.}

Correspondence: Beuy Joob; Sanitation 1 Medical Academic Center, Bangkok Thailand; E-mail: beuyjoob@hotmail.com

Conflict of interest: There is no conflict of interest to declare. Received 29 June 2017; Accepted 05 July 2017.

References

1. Linden VV, Linden Junior HV, Leal MC, Rolim Filho EL, Linden AV, Aragão MFVV et al. Discordant clinical outcomes of congenital Zika virus infection in twin pregnancies. Arq Neuropsiquiatr. 2017;75(6):381-6. https://doi.org/10.1590/0004-282x20170066 2. Wiwanitkit V. Placenta, Zika virus infection and fetal brain

abnormality. Am J ReprodImmunol. 2016;76(2):97-8. https://doi.org/10.1111/aji.12521

3. Wiwanitkit S, Wiwanitkit V. Afebrile, asymptomatic and

non-thrombocytopenic Zika virus infection: don’t miss it! Asian Pac J Trop Med. 2016;9(5):513. https://doi.org/10.1016/j.apjtm.2016.03.036 4. Zacharias N, Whitty J, Noblin S, Tsakiri S, Garcia J, Covinsky M et al.